Garrett 2860 -Or- 2871 ?

[Wheel House Motorsports]

So the main performance difference between the 2860 and 2876 is going to be a more linear boost and stronger top end with the 2876? I'll have to go to a bigger diameter charge tube also? And then up my fuel across the board or just in the bottom end?

Thanks! for the input skidooin.

no problem, i just know it works on a very logical basis, so explaining it makes a lot more sense then just saying, YOU NEED THIS NOW.

most likely could run the same charge tube, i think all of the turbos discussed run the same 2" outlet.. i prefer bigger charge tubes etc. but the physical inlet/outlets on the compressor side should be nearly identical.. exhasut side is the same.

benefits = better in and out of the throttle. hitting it from idle comes on much smoother and to say there is a little more on top is an understatment.. i would make an honest bet that if your currently running say 10# that you will pull the same clutching at 7# or less and have a much more rider friendly powerband.

as for fueling, im not knowledgable to say exactly what it will need as it does vary with how your box is setup. but you will need to retune a fair amount for it. but im betting what you will find is its much less touchy in how its tuned. with the higher power on lower boost, charge temps stay down helping deal with heat soaking, etc, so your state of tune stays much more consistant.

 

[knifedge]

--I think Twisted and OVS kits both run 2.5" charge tubes. This would help give more volume of air for off the bottom breathability as being discussed and lower charge temps.

 

[knifedge]

--I just checked the compressor map for the 2876

http://www.turbobygarrett.com/turbobygarrett/catelog/Turbochargers/GT28/GT2876R_705330_1.htm


--The 2876 flows under 50lb/min

--The FP HTA 2871 flows 51lb/min

http://www.ringer-racing.com/product.sc?productId=178&categoryId=181

--So with a OVS 2871 Hybrid you get the smaller compressor wheel for quicker spool but you also get better flow than the larger 2876. Then add an external wastegate on top of that and you get even faster spool and more efficient boost(less blowbly around turbine).

 

[knifedge]

--So the two best turbo options for the 800 may be:

--2871 with Tial external wastegate, the Forced Performance HTA compressor wheel and bigger ar housing

and/or

--2876 with the Tial external wastegate

--Take away the Tial wastegate and you lose efficiency(about 3lbs more needed for same power setting and you lose some throttle response(probably more noticeable off the bottom and midrange)

--Somewhere its mentioned OVS uses a bigger compressor housing on the 2871 which makes it a Hybrid 2871. It apparently flows like a 30 series but gives response like a 28 series. Also use a Tial turbine housing.

 

[WyoBoy1000]

So the main performance difference between the 2860 and 2876 is going to be a more linear boost and stronger top end with the 2876? I'll have to go to a bigger diameter charge tube also? And then up my fuel across the board or just in the bottom end?

Thanks! for the input skidooin.

The CPC stage 2 kit comes with 2 injectors, if I remember right so you will be running a lot less boost when you hit the limit of the 2 injectors but should have more performance. One guy stated he hardly changed anything when going from a 2860 to a 2876 and said it was very easy to tune. Thats just what I heard though. My sled has had a 2871 since the first owner in the beginning of 09, one of the first twisted kits with a bigger turbo I think, now they say 2876. 2 years ago tell now there must be something to the 2876, still learning though and hope to get a solid understanding on this stuff.

There is a lot of info and numbers out there that can get confusing, truth be told I will prob wait tell after snow flies then ask again and see what the thoughts of the actual turbo builders are, ie real world testing. Seems to be more accurate. But going off of what gus has said I think its a solid bet he's on top of it.

 

[ACMtnCat]

--The 2876 flows under 50lb/min

--The FP HTA 2871 flows 51lb/min.

These numbers tell me to go with the HTA 2871. But what about the 2876 with ported jugs? Anyone ever try that? I have a ported set sitting here.

 

[knifedge]

--There is a difference between turbo porting and normally asparated porting. Seems like it should still work though. Turbos work fine with factory N/A porting so why not N/A aftermarket porting, although maybe not optimum.

 

[Eli]

--I just checked the compressor map for the 2876

http://www.turbobygarrett.com/turbobygarrett/catelog/Turbochargers/GT28/GT2876R_705330_1.htm


--The 2876 flows under 50lb/min

--The FP HTA 2871 flows 51lb/min

http://www.ringer-racing.com/product.sc?productId=178&categoryId=181

--So with a OVS 2871 Hybrid you get the smaller compressor wheel for quicker spool but you also get better flow than the larger 2876. Then add an external wastegate on top of that and you get even faster spool and more efficient boost(less blowbly around turbine).

I am not sure that those max numbers tell the whole story. I'd like to see the shape of the 2868 compressor map.

As for fueling, when I went to the 2876 from a 2860, I did very little with fueling. Pretty much run the same settings. Twisted kit with Attitude box.

 

[theshadowrider]

I am not sure that those max numbers tell the whole story. I'd like to see the shape of the 2868 compressor map.

As for fueling, when I went to the 2876 from a 2860, I did very little with fueling. Pretty much run the same settings. Twisted kit with Attitude box.

What advantages did you see running the 2876 over the 2860?

Its interested what gus states

"NO, your still not even close to the flow a two stroke turbo needs to have good response UNDER boost.

the polaris guys are smoking engines, using foolish programming all to UNDOO the wrong they have done with the tiny aero and 2860.. heat and no flow are the causes of funky fuel curves and bogs and lack of boost over 700 feet."

I am not sure if gus is referring to the aero's or the 2860's? My experience is I am running a 2860 and my brother is running a 2876. Side by side I would say the 2876 is slightly less responsive on the low end before boost. The 2876 is on a skidoo 800 xp and the 2860 is on a dragon. Run them both at 12 psi at 10,000. When he rides my sled he always says I want mine as "snappy" as yours on and off power. After a season of tuning its pretty close, just feels a little laggier on the lowend. I know I am comparing apples to oranges but just my observation that it doesn't seem to be that big off difference between the two to justify switching turbos.

 

[WyoBoy1000]

What advantages did you see running the 2876 over the 2860?

Its interested what gus states

"NO, your still not even close to the flow a two stroke turbo needs to have good response UNDER boost.

the polaris guys are smoking engines, using foolish programming all to UNDOO the wrong they have done with the tiny aero and 2860.. heat and no flow are the causes of funky fuel curves and bogs and lack of boost over 700 feet."

I am not sure if gus is referring to the aero's or the 2860's? My experience is I am running a 2860 and my brother is running a 2876. Side by side I would say the 2876 is slightly less responsive on the low end before boost. The 2876 is on a skidoo 800 xp and the 2860 is on a dragon. Run them both at 12 psi at 10,000. When he rides my sled he always says I want mine as "snappy" as yours on and off power. After a season of tuning its pretty close, just feels a little laggier on the lowend. I know I am comparing apples to oranges but just my observation that it doesn't seem to be that big off difference between the two to justify switching turbos.

It all depends on tuning and who's kit,

 

[Wheel House Motorsports]

I am not sure if gus is referring to the aero's or the 2860's? My experience is I am running a 2860 and my brother is running a 2876. Side by side I would say the 2876 is slightly less responsive on the low end before boost. The 2876 is on a skidoo 800 xp and the 2860 is on a dragon. Run them both at 12 psi at 10,000. When he rides my sled he always says I want mine as "snappy" as yours on and off power. After a season of tuning its pretty close, just feels a little laggier on the lowend. I know I am comparing apples to oranges but just my observation that it doesn't seem to be that big off difference between the two to justify switching turbos.

The way the 2 motors feel is 100% different on boost to start, so that is goign to make a massive change in how they feel when riding.. and as for the last part. I can attest to that statment being very false.

each sled might run "well" but the differences in tuning and clutching is so differnt as your comparing carb to efi and normal clutches to a tra... the 2 biggest things i could thinking of changing when talking motors. the fueling tech on the dragons has infinately more time in it then the xp so your already almost cheating on that one having such a massive head start on "crisp running". also, there are a lot of stupid things on the xp's that go wrong and just dont make them run that impressive, again i think due to lack of knowledge/development on the doo's. one of the cleanest out of the hole sleds i have seen was a turbo xp i worked on.

AGAIN, having seen an t-800 with nothing but the turbo upgraded.. it is VERY worth it, the only way you can explain dropping from 8 down to 4.5# of boost with the same identical clutching is that its making a LOT more power.

 

[Dano702]

I upgraded to the 2876 on my ttm8. It was a big improvement over the 2871.The bottom end got better. And I ride thick trees alot, and my low rpm throttle response is super crispy.

 

[WyoBoy1000]

When everyone is talking about the 2876, are you running a .64 housing or what.

 

[Wheel House Motorsports]

When everyone is talking about the 2876, are you running a .64 housing or what.

nope... still the .86. you run the EXACT same exhaust side as a 2860 or a 2871. the exhaust housing and wheels are totally interchangable on them, all thats being changed is the compressor wheel and housing.

the .64 housings beings discussed are on the 30XX turbo's as they are the bigger exhaust side. the 30 with a .64 flows very similar exhaust to the 28 with a .86.

 

[WyoBoy1000]

So what all would I need to change my 2871-2 to a 2876.

 

[theshadowrider]

So what all would I need to change my 2871-2 to a 2876.

And the best place to get these parts from?

 

[knifedge]

http://www.atpturbo.com/mm5/merchant.mvc?Screen=CTGY&Store_Code=tp&Category_Code=GCH


http://www.atpturbo.com/mm5/merchant.mvc?Screen=CTGY&Store_Code=tp&Category_Code=GCH

http://www.atpturbo.com/mm5/merchan...uct_Code=GRT-CWH-001&Category_Code=COMPWHEELS

--Just convert your existing 2871 to this housing and compressor wheel and now you have the Hybrid that flows better than the 2876 but spools like the 2871. You will need a 2.5 inch Diam. charge tube from Twisted or whoever and it has a 4 inch Inlet.. Total cost under $500 bucks.

--Disclaimer--Verify these components are what you want. This setup is just an opinion formed by reading through these threads.

 

[knifedge]

--I believe I woud check into the above setup be for spending $1400 for an entirely new turbo.

 

[jijohans]

Anyone tried the 2876 .86 @ sealevel?

 

[gus bohne]

That is where we ride and race JJohans.. I am at sea level and go no higher than 2200 feet above.

the 2876 makes boost at sealevel around 2700 rpm on the 800 rev.

Gus